Tumorigenesis by oxygenated nitrosopiperidines in rats

Three oxygenated N-nitrosopiperidines--nitroso-3-piperidinol, nitroso-4-piperidinol, and nitroso-4-piperidone--were prepared and given in drinking water at equivalent molar doses to Sprague-Dawley rats. All were potent carcinogens, 100% of the rats developed tumors in all treatment groups. Nitroso-3-piperidinol resembled nitrosopiperidine in inducing a high incidence of tumors of the nasal cavity and upper alimentary tract, and a few liver tumors. Nitroso-4-piperidinol and nitroso-4-piperidone caused a high incidence of tumors of the nasal cavity but very few tumors of the upper alimentary tract. After treatment with the 4-substituted compounds, a high incidence of liver tumors was observed in females but not in males.